@article{JRAM_1987__382_152987,
     author = {B. Drachman and S.A.van Gils},
     title = {Abelian integrals for quadratic vector fields.},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {165--180},
     year = {1987},
     volume = {382},
     zbl = {0621.58033},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1987__382_152987/}
}